Dafoe Nicole J, Constabel C Peter
Centre for Forest Biology and Department of Biology, P.O. Box 3020, Station CSC, Victoria, Canada BC V8W 3N5.
Phytochemistry. 2009 May;70(7):856-63. doi: 10.1016/j.phytochem.2009.04.016. Epub 2009 May 23.
Xylem sap collected from Populus trichocarpaxPopulus deltoides using root pressure was estimated to contain more than 100 proteins. Ninety-seven of these proteins were identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These proteins were classified into 10 functional categories including metabolism, signaling, stress response and cell wall functions. The majority of xylem sap proteins were metabolic enzymes involved in processes including translation, proteolysis, and glycolysis. Stress-related proteins were also prevalent. In contrast to xylem sap proteins collected from annual plants, the majority of poplar xylem sap proteins do not appear to be classically secreted since only 33 proteins were predicted to have an N-terminal signal peptide targeting them to the secretory pathway. Of the remaining 64 proteins, 27 were predicted to be secreted non-classically. While a number of proteins identified here have been previously reported in xylem sap proteomes of annual plants, many xylem sap proteins were identified in poplar which may reflect functions specific to perennial plants.
利用根压从毛果杨×美洲黑杨收集的木质部汁液估计含有100多种蛋白质。其中97种蛋白质通过液相色谱 - 串联质谱法（LC-MS/MS）得到鉴定。这些蛋白质被分为10个功能类别，包括代谢、信号传导、应激反应和细胞壁功能。大多数木质部汁液蛋白质是参与翻译、蛋白水解和糖酵解等过程的代谢酶。与应激相关的蛋白质也很普遍。与从一年生植物收集的木质部汁液蛋白质不同，大多数杨树木质部汁液蛋白质似乎并非经典分泌型，因为预计只有33种蛋白质具有将它们靶向分泌途径的N端信号肽。在其余64种蛋白质中，预计有27种通过非经典方式分泌。虽然这里鉴定出的许多蛋白质先前已在一年生植物的木质部汁液蛋白质组中报道过，但杨树中鉴定出了许多木质部汁液蛋白质，这可能反映了多年生植物特有的功能。
